scoreboard.hh revision 9916:9c3a4595cce9
1/* 2 * Copyright (c) 2005-2006 The Regents of The University of Michigan 3 * Copyright (c) 2013 Advanced Micro Devices, Inc. 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions are 8 * met: redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer; 10 * redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution; 13 * neither the name of the copyright holders nor the names of its 14 * contributors may be used to endorse or promote products derived from 15 * this software without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 18 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 19 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 20 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 21 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 22 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 23 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 27 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 28 * 29 * Authors: Korey Sewell 30 * Kevin Lim 31 * Steve Reinhardt 32 */ 33 34#ifndef __CPU_O3_SCOREBOARD_HH__ 35#define __CPU_O3_SCOREBOARD_HH__ 36 37#include <iostream> 38#include <utility> 39#include <vector> 40 41#include "base/trace.hh" 42#include "config/the_isa.hh" 43#include "cpu/o3/comm.hh" 44#include "debug/Scoreboard.hh" 45 46/** 47 * Implements a simple scoreboard to track which registers are 48 * ready. This class operates on the unified physical register space, 49 * so integer and floating-point registers are not distinguished. For 50 * convenience, it also accepts operations on the physical-space 51 * mapping of misc registers, which are numbered starting after the 52 * end of the actual physical register file. However, there is no 53 * actual scoreboard for misc registers, and they are always 54 * considered ready. 55 */ 56class Scoreboard 57{ 58 private: 59 /** The object name, for DPRINTF. We have to declare this 60 * explicitly because Scoreboard is not a SimObject. */ 61 const std::string _name; 62 63 /** Scoreboard of physical integer registers, saying whether or not they 64 * are ready. */ 65 std::vector<bool> regScoreBoard; 66 67 /** The number of actual physical registers */ 68 unsigned numPhysRegs; 69 70 /** 71 * The total number of registers which can be indexed, including 72 * the misc registers that come after the physical registers and 73 * which are hardwired to be always considered ready. 74 */ 75 unsigned numTotalRegs; 76 77 /** The index of the zero register. */ 78 PhysRegIndex zeroRegIdx; 79 80 /** The index of the FP zero register. */ 81 PhysRegIndex fpZeroRegIdx; 82 83 bool isZeroReg(PhysRegIndex idx) const 84 { 85 return (idx == zeroRegIdx || 86 (THE_ISA == ALPHA_ISA && idx == fpZeroRegIdx)); 87 } 88 89 public: 90 /** Constructs a scoreboard. 91 * @param _numPhysicalRegs Number of physical registers. 92 * @param _numMiscRegs Number of miscellaneous registers. 93 * @param _zeroRegIdx Index of the zero register. 94 * @param _fpZeroRegIdx Index of the FP zero register (if any, currently 95 * used only for Alpha). 96 */ 97 Scoreboard(const std::string &_my_name, 98 unsigned _numPhysicalRegs, 99 unsigned _numMiscRegs, 100 PhysRegIndex _zeroRegIdx, 101 PhysRegIndex _fpZeroRegIdx); 102 103 /** Destructor. */ 104 ~Scoreboard() {} 105 106 /** Returns the name of the scoreboard. */ 107 std::string name() const { return _name; }; 108 109 /** Checks if the register is ready. */ 110 bool getReg(PhysRegIndex reg_idx) const 111 { 112 assert(reg_idx < numTotalRegs); 113 114 if (reg_idx >= numPhysRegs) { 115 // misc regs are always ready 116 return true; 117 } 118 119 bool ready = regScoreBoard[reg_idx]; 120 121 if (isZeroReg(reg_idx)) 122 assert(ready); 123 124 return ready; 125 } 126 127 /** Sets the register as ready. */ 128 void setReg(PhysRegIndex reg_idx) 129 { 130 assert(reg_idx < numTotalRegs); 131 132 if (reg_idx >= numPhysRegs) { 133 // misc regs are always ready, ignore attempts to change that 134 return; 135 } 136 137 DPRINTF(Scoreboard, "Setting reg %i as ready\n", reg_idx); 138 139 assert(reg_idx < numTotalRegs); 140 regScoreBoard[reg_idx] = true; 141 } 142 143 /** Sets the register as not ready. */ 144 void unsetReg(PhysRegIndex reg_idx) 145 { 146 assert(reg_idx < numTotalRegs); 147 148 if (reg_idx >= numPhysRegs) { 149 // misc regs are always ready, ignore attempts to change that 150 return; 151 } 152 153 // zero reg should never be marked unready 154 if (isZeroReg(reg_idx)) 155 return; 156 157 regScoreBoard[reg_idx] = false; 158 } 159 160}; 161 162#endif 163